Hyperthyroidism - Graves' disease

Question 1

Is Graves’ disease more common in men or women?

Answer 1

More common in women.

Question 2

What is the pathophysiology of Graves’ disease?

Answer 2

Anti-TSH receptor antibodies cause thyroid hormone overproduction as well as thyroid hypertrophy and hyperplasia of thyroid follicular cells.

Question 3

What is the aetiology of Graves’ disease?

Answer 3

· Stimulation of the thyroid by TSH receptor antibodies.

· Although other thyroid antibodies occur in people with Graves’ disease, they don’t play a part in the development of hyperthyroidism.

· Combination of genetic (80%) and environmental (20%) factors.

· Graves’, toxic nodular goitre, thyroid adenoma, thyroiditis, too much levothyroxine.

Question 4

List the common risk factors.

Answer 4

· FHx of autoimmune thyroid disease.
· Female sex.
· Tobacco use.

Question 5

List the signs and symptoms.

Answer 5

· Heat intolerance.
· Sweating.
· Weight loss.
· Palpitations.
· Nervousness and anxiety. 
· Tremor. 
· Increased appetite. 
· Tachycardia. 
· Changes in bowel habit.
· Diffuse goitre.
· Menstrual irregularity - slow down or stop. 
· Orbitopathy:
- Clinically present in 25% of patients. 
- Upper eyelid retraction is present in over 90% of cases. 
- Exophthalmos/Optic neuropathy. 
- Extraocular muscle involvement. 
· Onycholysis - detachment of nail from nail bed. 
· Pretibial oedema.

Question 6

Why does heat intolerance occur?

Answer 6

Because an increased metabolism leads to a higher body temperature.

Question 7

Why does weight loss occur?

Answer 7

Because there is an accelerated metabolism and higher basal metabolic rate.

Question 8

What changes in bowel habits occur?

Answer 8

Patient has increased frequency with looser stools.

Question 9

What investigations would you request if you suspected a patient had Graves’ disease?

Answer 9

· TSH.
· Serum free or total T4.
· Serum free or total T3.

Question 10

What would the investigation results typically show?

Answer 10

· TSH - Suppressed.
· Serum free or total T4 - Elevated.
· Serum free or total T3 - Elevated.

Question 11

Suggest some differentials.

Answer 11

· Toxic nodular goitre.
· Painless and postnatal thyroiditis.
· TSH-producing pituitary adenoma.

Question 12

What is the treatment for an acute thyroid storm?

Answer 12

· 1st line - High dose anti-thyroid drugs, corticosteroids, beta blockers and iodine solution with supportive care.
· Adjunct - Colestyramine.
· Adjunct - Lithium.

Question 13

What are the treatment options for Graves’ disease in adults?

Answer 13

· 1st line - Prolonged anti-thyroid drug therapy.
· Symptomatic therapy.
· Radioactive iodine for treatment failure.
· Radioactive iodine +/- corticosteroid.
· Thyroid surgery.

Question 14

What complications can arise?

Answer 14

· Bone mineral loss. Related to the duration of untreated hyperthyroidism.
· AF.
· Congestive heart failure.
· Sight-threatening complications of Graves’ orbitopathy.